1. Field of the Invention
The invention relates to vacuum cleaners, and in particular to wet/dry vacuum cleaners. The invention also relates to so-called cyclonic vacuum cleaners which use a circulating airflow to separate contaminants from the air.
2. Background Information
Wet/dry vacuum cleaners are well-known. Such vacuum cleaners separate liquid and contaminants from a suction stream of air. The liquid and contaminants are collected in a collection chamber for later emptying. It is also known to put a level switch, such as a float switch, in the collection chamber to stop the vacuum cleaner motor when a level of liquid in the collection chamber rises to a predetermined level.
Cyclonic vacuum cleaners that use circular airflow within a separation chamber to separate liquid and contaminants from a stream of air are also known. Typically, a separation chamber is provided in an upper portion of a cyclone housing, with the lower portion of the housing forming a collection chamber for the separated liquid and contaminants. The circular airflow causes circular movement of water in the collection chamber. A problem with placing a level switch within the collection chamber of a cyclone vacuum cleaner is that the circular movement of water in the collection chamber results in inaccurate level measurement.
A second problem is that it is difficult to get a stream of air laden with heavy water to move in a circular motion within the separation chamber in order to separate the liquid and contaminants from the air stream.